As the model bases allow for easy removal of individual sections of the dental model, lack of stability of the sections can occur which can seriously affect the accuracy of restorations. Pending European patent application EP 1097678 of the same inventor addresses this issue by utilising an A-frame within the mould to allow pins to extend through the mould and secure the dental model thereto.
In use, material is poured into the mould and solidifies to form the dental model. Suitable materials for pouring into the mould are plaster or artificial stone. A typical material for the dental model is α-hemihydrate of calcium sulphate. Preferably, the material has a hardness range which allows cutting thereof during sectioning of the model cast.
A problem with known moulds is that to remove the dental model from the mould, a high force is frequently required to overcome the adherence between the mould and the dental model, and a hammer is typically used to strike the mould. This can often result in undesirable damage to the dental model, especially if the hammer is caused to contact the model by mistake.
In addition a dental model is required to be cut into sections so that work can be carried out on each individual section. Repositioning of the individual sections within the mould can adversely result in misalignment, especially in the case that some damage has occurred during ejection of the model from the mould.
The aim of the present invention is to provide a model base which is of improved form and allows the improved removal of the dental model from the mould.